1. Field
The present invention relates generally to communications, and more specifically, to a method and apparatus for charging for information services in a wireless communication system employing a broadcast-multicast communication service (BCMCS).
2. Background
Broadcast-multicast services (BCMCS) provide point-to-multipoint communication service in a wireless communication system to a plurality of mobile stations that receive the broadcast data through a wireless communication medium. The broadcast data (i.e., content) transmitted by the wireless communication system to the plurality of mobile stations may include, but need not necessarily be limited to, news, movies, sporting events, and the like. The specific type of content transmitted to the mobile stations may include a wide array of multi-media data, such as text, audio, picture, streaming video, etc. The content is typically generated by a content provider and is broadcast to the mobile stations that subscribe to the particular service over a broadcast channel of the wireless communication system.
The broadcast content is typically encrypted and decrypted through several levels of encryption and decryption to provide at least some level of assurance that unauthorized users will not be able to decrypt the content to which they are not entitled (i.e., content that is not subscribed to by the user of the mobile station). To enable the encryption and decryption of the broadcast content, the broadcast-multicast service employs the use of encryption keys.
A long-term encryption key, commonly referred to as a broadcast access key (BAK), is provisioned into the memory of the mobile station by the broadcast-multicast service. A short-term key (SK) is derived from the broadcast access key BAK and a random number SKRAND. The content is encrypted with the short-term key SK, and is broadcast over the air to the mobile station by the wireless communication system along with the random number SKRAND. The mobile station computes the short-term key SK from the random number SKRAND and the broadcast access key BAK, and decrypts the received content using the short-term key SK for presentation of the content to the mobile station's user.
Typically, the user of the mobile station is charged for the broadcast content upon receipt of the broadcast access key BAK. Therefore, regardless of whether or not the user is actually viewing the broadcast content from the broadcast-multicast service, the user is charged upon receipt of the broadcast access key (BAK). When the user is charged for broadcast content that he or she is not currently viewing, the user is burdened with these additional expenses incurred unnecessarily.
The present invention is directed to overcoming, or at least reducing the effects of, one or more problems set forth above.